Changeset 12f91130 in mainline

Timestamp:

2007-06-28T15:49:21Z (17 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

9591265

Parents:

bc1f1c2

Message:

Remove fibril_join().
We cannot guarantee our assumptions that easily.
This broken feature is removed instead of fixing because there are now users of it.

Location:

uspace/lib/libc

Files:

• generic/async.c (modified) (1 diff)
• generic/fibril.c (modified) (12 diffs)
• include/fibril.h (modified) (3 diffs)

uspace/lib/libc/generic/async.c

@@ -52 +52 @@
  * 
  * 1) Multithreaded client application
- *  create_thread(thread1);
- *  create_thread(thread2);
+ *  fibril_create(fibril1);
+ *  fibril_create(fibril2);
  *  ...
  *  
- *  thread1() {
+ *  fibril1() {
  *        conn = ipc_connect_me_to();
  *        c1 = send(conn);

uspace/lib/libc/generic/fibril.c

@@ -49 +49 @@
 #endif
 
+/** This futex serializes access to ready_list, serialized_list and manage_list.
+ */ 
+static atomic_t fibril_futex = FUTEX_INITIALIZER;
+
 static LIST_INITIALIZE(ready_list);
 static LIST_INITIALIZE(serialized_list);
@@ -55 +59 @@
 static void fibril_main(void);
 
-static atomic_t fibril_futex = FUTEX_INITIALIZER;
-/** Number of threads that are in async_serialized mode */
-static int serialized_threads;  /* Protected by async_futex */
+/** Number of fibrils that are in async_serialized mode */
+static int serialized_fibrils;  /* Protected by async_futex */
 /** Thread-local count of serialization. If >0, we must not preempt */
 static __thread int serialization_count;
@@ -93 +96 @@
 /** Function that spans the whole life-cycle of a fibril.
  *
- * Each fibril begins execution in this function.  Then the function
- * implementing the fibril logic is called.  After its return, the return value
- * is saved for a potentional joiner. If the joiner exists, it is woken up. The
- * fibril then switches to another fibril, which cleans up after it.
+ * Each fibril begins execution in this function. Then the function implementing
+ * the fibril logic is called.  After its return, the return value is saved.
+ * The fibril then switches to another fibril, which cleans up after it.
  */
 void fibril_main(void)
@@ -102 +104 @@
         fibril_t *f = __tcb_get()->fibril_data;
 
+        /* Call the implementing function. */
         f->retval = f->func(f->arg);
-
-        /*
-         * If there is a joiner, wake it up and save our return value.
-         */
-        if (f->joiner) {
-                list_append(&f->joiner->link, &ready_list);
-                f->joiner->joinee_retval = f->retval;
-        }
 
         fibril_schedule_next_adv(FIBRIL_FROM_DEAD);
@@ -121 +116 @@
  * held.
  *
- * @param stype         One of FIBRIL_SLEEP, FIBRIL_PREEMPT, FIBRIL_TO_MANAGER,
+ * @param stype         Switch type. One of FIBRIL_PREEMPT, FIBRIL_TO_MANAGER,
  *                      FIBRIL_FROM_MANAGER, FIBRIL_FROM_DEAD. The parameter
  *                      describes the circumstances of the switch.
@@ -136 +131 @@
         if (stype == FIBRIL_PREEMPT && list_empty(&ready_list))
                 goto ret_0;
-        if (stype == FIBRIL_SLEEP) {
-                if (list_empty(&ready_list) && list_empty(&serialized_list))
-                        goto ret_0;
-        }
 
         if (stype == FIBRIL_FROM_MANAGER) {
@@ -145 +136 @@
                         goto ret_0;
                 /*
-                 * Do not preempt if there is not sufficient count of thread
+                 * Do not preempt if there is not sufficient count of fibril 
                  * managers.
                  */
                 if (list_empty(&serialized_list) && fibrils_in_manager <=
-                    serialized_threads) {
+                    serialized_fibrils) {
                         goto ret_0;
                 }
@@ -191 +182 @@
                          * any list, we should already be somewhere, or we will
                          * be lost.
-                         *
-                         * The stype == FIBRIL_SLEEP case is similar. The fibril
-                         * has an external refernce which can be used to wake it
-                         * up once that time has come.
                          */
                 }
@@ -203 +190 @@
                 dstf = list_get_instance(manager_list.next, fibril_t, link);
                 if (serialization_count && stype == FIBRIL_TO_MANAGER) {
-                        serialized_threads++;
+                        serialized_fibrils++;
                         srcf->flags |= FIBRIL_SERIALIZED;
                 }
@@ -214 +201 @@
                         dstf = list_get_instance(serialized_list.next, fibril_t,
                             link);
-                        serialized_threads--;
+                        serialized_fibrils--;
                 } else {
                         dstf = list_get_instance(ready_list.next, fibril_t,
@@ -229 +216 @@
         futex_up(&fibril_futex);
         return retval;
-}
-
-/** Wait for fibril to finish.
- *
- * Each fibril can be only joined by one other fibril. Moreover, the joiner must
- * be from the same thread as the joinee.
- *
- * @param fid           Fibril to join.
- *
- * @return              Value returned by the completed fibril.
- */
-int fibril_join(fid_t fid)
-{
-        fibril_t *f;
-        fibril_t *cur;
-
-        /* Handle fid = Kernel address -> it is wait for call */
-        f = (fibril_t *) fid;
-
-        /*
-         * The joiner is running so the joinee isn't.
-         */
-        cur = __tcb_get()->fibril_data;
-        f->joiner = cur;
-        fibril_schedule_next_adv(FIBRIL_SLEEP);
-
-        /*
-         * The joinee fills in the return value.
-         */
-        return cur->joinee_retval;
 }
 
@@ -286 +243 @@
         f->func = func;
         f->clean_after_me = NULL;
-        f->joiner = NULL;
-        f->joinee_retval = 0;
         f->retval = 0;
         f->flags = 0;

uspace/lib/libc/include/fibril.h

@@ -50 +50 @@
 
 typedef enum {
-        FIBRIL_SLEEP,
         FIBRIL_PREEMPT,
         FIBRIL_TO_MANAGER,
@@ -68 +67 @@
 
         struct fibril *clean_after_me;
-        struct fibril *joiner;
-        int joinee_retval;
         int retval;
         int flags;
@@ -79 +76 @@
 
 extern fid_t fibril_create(int (*func)(void *), void *arg);
-extern int fibril_join(fid_t fid);
 extern fibril_t *fibril_setup(void);
 extern void fibril_teardown(fibril_t *f);